Compressor



D. C. BAKER.

COMPRESSOR.

APPLICATION FILED ocnze, 1920.

Patented Sept. 19, 1922..

4 SHEETS-SHEET l.

n. c. BAKER. coMPREsson.

' APPLICATION FILED ocnze, I920.

Patented Sept.- 19, 1922.

4 SHEETS-SHEET 2. I

I u. c. BAKER. I COMPRESSOR.

APPLICATION FILED OCT. 26.1920.

qgg gg PatentedSept'.19,1922.

4 SHEETS-SHEET a.

D. C. BAKER.

COMPRESSOR.

APPLICATION FIL'ED on. 26. 1 920.

Patented Sept. 19, 1922.

4 SHEETS-SHET 4.

D (NM W m k W Z a TOR WITNESS A TTORNE YS Patented Sept. 19, 1922 EAZFFZF PATENT @FFllQltL DEXTER C. BAKER, OF OAKLAND, CALIFORNIA, ASSIGNOR TO BAKER-HANSEN MANU- FACTURING COMPANY, OF OAKLAND, CALIFORNIA.

COMPRESSOR.

Application filed October 26, 1920. Serial No. 419,714.

To all whom it may concern.

Be it known that I, DEXTER C. BAKER, a citizen of the United States, and resident of Oakland, county of Alameda, State of California, have invented a new and useful Compressor, of which the following is a specification.

The present invention, while relating in general to the art of air and gas pumps, has reference more particularly to an improvement in air compressors for creating a suitable source of compressed .air such, formstance, as is used in air brake systems and in other capacities where it is necessary to realize upon a store of compressed air source.

In so far as concerns the preferred embodiment of the invention, it isproposed to provide a single unit compressor,including a pair of rectilinear single-acting pistons, both. of which being driven by an eccentric drive. lVith this construction in view, and by means of the novel valve arrangement for controlling the effective port area of the intakes and outlets for introducing the air to be acted upon by the pistons and subsequently stored or, rather, delivered to the storage tank or other like container, it is possible to realize an exceedingly practical solution of the problems involved in an apparatus of this character.

That form of the invention which has been selected for the purpose of illustration is shown on the accompanying draw, ings, in which Figure -1 is a plan view of the compressor; Figure 2 is a view in ele-- vation of one of the end plates; Figure 3 is a View in elevation of the opposite end plate; Figures 4 to 7 inclusive are side elevations of the valve arrangement for both ends of the compressor; Figure 8 is a view in cross-section through the middle of the compressor and showing the journal bearing for the drive shaft; Figure 9 is a side view of the drive shaft, including the pitman, and showing the anti-friction bearings in longitudinal section; Figure 10 is an end view of the drive shaft, including the pitman, and showing the anti-friction bearing for the pitman in elevation, and Figure 11 is a horizontal section through the compressor as assembled, and showing thev eo-operative relationship of the parts,

Referring now to the drawings in detail, attention is invited to Figures 1 and 11, from which it will be noted that one of the salient features of the inventionresides in the relatively small dimensions of the assembled construction. This desirable feature is realized by the construction and operat ve association of the parts without sacrificing the capacity of the compressor for creating the desired air pressure; in other words, while it is obvious that the compressor may be made in different sizes to accommodate the same to different uses, without departing from the spirit of the lnventlon, the peculiar construction and practical-arrangement of the parts will enable the compressor to function with a greater efliciencythan those compressors heretofore employed.

According to the present illustration, the compressor includes a pair of cylinders of different stages, each of which having a piston corresponding in size to its respective cylinder. This should not be considered as a limitation, as in some cases it may be desirable to arrange the cylinders and the pistons therefor in more or less equal size and capacity.

. As will be seen, it is preferred to employ a pair of opposed co-axial cylinders (1) and (2), each of which for cooling purposes being provided with the customarv fins or the like (3) and joined end to end by a middle section or crank case (4), the same having a greater diameter at one end than the other to accommodate it to the small and large cylinders (1) and (2) respectively.

As a convenient means of assembling the cylinders and the section (4) rods (5) may be carried by the section (4) with openings in the fins (3) of each of the cylinders through which the rods are passed and with the rodsterminatingin threads made to receive the nuts (6); I

Theends or heads of each of the cylinders (l) and (2) are closed by suitable plates (7) and (8) which are provided with openings through which the rods (5) pass with the nuts (6) arranged on the outer faces of the plates. These plates also include air ports, which will be presently described.

As will be seen more clearly from Figures 1 and 8, the middle section or crank case (4) includes a transverse journal bearing (9) which enters the crank case from the side thereof to provide a bearing for the drive shaft (10) which also has associated with it the anti-friction bearing (11) which is of a diameter substantially that of the journal bearing (9)so as to provide a tight fit. Arranged on the outer end of the journal'bearing (9) is a sleeve or collar (12) which has an axial bore of substantially the diameter of the shaft (10) so as to restrict the opening of the journal bearing (9) to a size of that of the shaft and thus close the end of the samei A suitable standard or the like (13) is employed to encircle the journal bearing (9), with its opposite end providing a support.

The drive shaft (10) terminates on its inner end in a so-called crank which primarily comprises a block (1 1) which is eccentrically mounted upon the end of the shaft and with a short crank pin (15) eccentri'cally mounted upon the face of the block (14f) and extending outwardly therefrom parallel to the shaft (10). Carried by the short crank shaft (15) isthe anti-friction device (16). The crank is adapted to be introduced into the crank case (4:) and assume a position substantially intersecting the axis of the cylinders (1)] and (2).

As previously mentioned, each one of the cylinders is adapted to house its respective piston, said pistons being arran ed in rec- 1 tilinear alignment and represented as at (17) and the same piece.

will be presented at right angles to the 2LX1S' and (18). The piston (17), which is constructedto accommodate it to the larger one of the cylinders, is preferably hollow to re duce its weight owing to its larger diameter than the piston (18), but the same will also include a relatively large axial and rearwardly extending part (19) which terminates suliistantially in alignment with the inner periphery of the pistons to provide a radial shoulder bearing (20). This does not mean that the part (19) is abruptly cut off to provide the shoulder (20) as in reality, and as best shown in Figure 8, the reduced thickness of the memb'erprovides a continuation (21) to connect the piston (18) to make both of the pistons practically one The continuation (21) of the shaft (10) so as to enable the pitman to be introduced and confined between the radial shoulder (20) on the piston (17) and a like radial shoulder on the piston (18). The surfaces of the shoulder (20) and the shoulder (22) are parallel to one an other and the space bet-ween them is of substantially the same dimension as the diameter of the ball-bearing anti-friction device (16) of the pitma'n. Owing to the small diameter of the piston (18) it will not be necessary to llOllOW the same out as in the case of the piston (17). For this reason it. may be solid.

Both of the pistons will be equipped with rings (23) and (24:).

With the pitman confined between the shoulders (20) and (22) of the pistons, and

by imparting a suitable rotary drive to the shaft (10) the eccentric of the pitman will convert the rotary movement of the shaft into a reciprocating motionof the pistons.

the working cylind'er'swhere it will be acted upon by the pistons and delivered to a point where it may be stored,attention is directed to the valves and ports associated with the end plates or heads (7) and (8). present showing, the piston (17) may be said to introduce or suck the air into the compressor, whereas the piston (18) is a secondary compressing medium in that, while it does not introduce the air from the atmosphere into its respective cylinder, it acts upon the air which has been transferred from the cylinder (2) by the piston (17) into the cylinder (1); therefore, the primary intake is located in the plate or head (8) and may be represented by the plurality of ports (25) which are arranged in spaced relation around the head and com municate "directly with the compression chamber of the cylinder (2) in front of the piston (17). The valve or means for opening' these intakes upon the suction stroke of the piston (17) and closing 'them'upon'the compression stroke of the same, comprises a relatively thin flexible disc (26) which is of such diameter that when centered on the inner'fa'ce of the head (8) the edge thereof will overlap the openings Considering the disc (26) as being maintained flat against the inner face of the head by the centering and holding bolt (27) and par ticularly as the inner face of the head is slightlyconcave and, furthermore, by using a pair of auxiliary discs (28) and (29) to overlay the inner dimensions of the disc (26), theouter periphery or edge of the disc (26) is more or less flexible, with its central part maintained rigid and flat against the concave 'of, the head as mentioned. With this construction contemplated, a suction stroke of the piston (17) will operate to flex the edge of the disc (26) and move it slightly from itss'ealing posiand spaced apart, are a plurality of openings ('30) which effect a communication between the compression chamber of the cylinder (2) and distributing chamber (31) which is formed by the housin These openings are normally unobstructed so far as In the I lOO ' ch a mber (31) concerns the passage of air from the compression chamber of the cylinder to the distributing chamber (31); at least the discs (26) and (28) are perforated as at and the perforations never change their position with reference to the openings to the extent that the openings will be obstructed. At the same time, a second set of disc valves are employed within the distrilniting chamber (31) to seal the openings (30) against back pressure from the dist: but Q chamber (81) to the compression chamber of the cylinder (2). One of these discs, i. e, is of a diameter suilicicnt to overlap the openings when the ear is centered upon the bolt The face 01 the head (8) Within the distributing sl'ghtl concave and an auxiliary disc is caused to overlay the inner dii'ncnsion oi" the disc (34:) to add rigidity to the same, the same time permitting its outer edge to flex so that when upon the compression stroke 01" the piston (1'7) the air )reviouslyladmitted, by the suction stroke into the compression chamber will be forced through the openings (33) in the discs through the openings (30), the pressure thereof causing the edge of the disc (34:) to flex and permit the to be forced into the distributing chamber (31). Upon the suction stroke of the piston (17) the edge of the disc (34) will be caused by re suction to overlap the openings and seal the same in so far as concerns the distributing chamber (81).

From the above it will be seen that these discs are in many respects flexible diaphragms and that they are used in the capacity ot-valves. Of course it should be understood that the showing; made in Figure 11 does not represent the true active position of the discs one to the other, nor to the head (8), as in this figure they are shown spaced apart to distinguish the same one from the other They may be readily clamped into proper position by screwing up on the nut (36) of the bolt (27).

i articular notice should be given the annu ar grooves (25) arranged on the inside of the openings and the annular grooves and (30) which are arranged on the inner and outer sides respec tively of the openings This construction in fact is really an annular continuation of the openings (25) around the inside or the plate or head 8) and an annular continuation of the openings on both the inside and outside of the plate or head Vi hen the air alter being sucked into the compression chamber of the cylinder has been transferred into the distributing chamber ot the housing by a compression stroke of the piston (17), it is transferred to and acted upon by the piston (18) and to realize this transfer a connec* tion (3'?) is arranged in the housi. (32) with a tubing or the like (38) fixed to the connection and extending in any suitable manner around the compressor and communicating with the connection (39) which is arranged in the housing (40) which is connected to the head or plate of the cylinder The plate or head (7) includes a slightly modified construction from that oi the plate or head (8) in that it comprises annular outer groove (41) which is adapted to comiunicate with a hollowed out portion (42) of tne housing (40) so that the air transferred through the tubing (38) may be introduced into this annular groove H). Arranged in the thickness of the plate and an angle to the annular groove (4-!) are a plurality of openings or ducts (as) which terminate inwardly in the comparatively narrow annular groove (44); consequently the ducts establish a communication between the tubing (38) and the compression chamber of the cylinder in very much the same manner as the openings establish a communication from the atmosphere in to the compression chamber of the cylinder The annular groove (4-4) acts in the same capacity as the annular groove (25) at the other end of the compressor. As a means for overlapping and closing the ducts a disc (45) is centered upon the bolt 16) with its edge overlapping the groove (44:) and with a secondary disc i-7) co-axially placed upon the bolt (46) to maintain the disc rigid against the slightly concave inner face of the plate (7) so that the air in being forced through the tubing may occupy the compression chamber 01" the cylinder (1) by flexing the edge of the disc (45) at a point where it overlaps the groove (44). It is to be noted that when the piston (17) is on a compression stroke which would act to force air through the tubing (38), the piston (18) is on a suction stroke; therefore, the air is not only forced through the tubing (38) but it is also sucked th-ercthrough, or looking at the function in a different light, it may be said that the piston (18) in ellect produces a vacuum on its suction stroke which will enable the air to be readily introduced into the cylinder.

Arranged in the plate or head (7) inwardly of the ducts (43) are a plurality of openings (48) which are really a duplication of the openings in that annular grooves (48) and (4-8) are arranged on opposite sides of the plate (7) and the openings es tablish a communication between the comprcssion chamber in front of the piston (18) into the chamber (49) 01" the housing (40). This communication is always open from the inside of the compression chamber by means of an opening (50) arranged in the disc in front of each ofthe openings (as Carried upon the centering bolt (46) within the chamber (49) is a disc (51) which is of a dimension sufficient to overlap the groove (48 and adapted to bear against the concave outer face of the plate. This disc in overlapping the groove (48) provides a valveclosure for the opening (48) from the chamber (49) into the compression chamber of the cylinder, but upon a compression stroke of the piston (18) the edge oi this disc is flexed to permit the piston to transfer the air from the compression chamher into the chamber (49). Overlapping this disc (51) is an auxiliary disc which is likewise centered upon the bolt (as) to add rigidity to thecenter dimension of the disc as in the case of the other discs,

The position of the discs (45), (47), (51) and (52) is abnormal in that they are shown spaced apart to distinguish them one from the other. They may be clamped in the proper active position by screwing up on the nut (53) as explained with reference to the opposite end of the compressor.

Communicating with thechamber (49) is a connection comprising a check valve (5 which is adapted to connect with a piping or tubing for delivering the compressed air created by the compressor into a suitable storage.

Arranged in the base of the crank case t) is an oil basin (55). (See Figure 8). The top of the crank case is equipped with breather openings (56).

I claim:

1. In an air compressor, a pair of co-axi-v ally arranged cylinders, a pair of rectilinear pistons in said cylinders, said pistons being made as a unitary structure with a connectmg web eccentrically positloned relative to the axis of the pistons, and adrive for said inner ends of the pistons transversely of the axis thereof and opposite the said connecting web, one of said pistons having a larger diameter than the other with the said cylinders made correspondingly, the smaller one of said pistons comprising a solid structure and the larger one being a hollow with an axial annular solid block-like structure within its hollow, the diameter of said-blocklike structure being equal to that of the diameter of the smaller solid piston and arranged co-axially thereof.

2. In an air compressor, a pair of co-axially arranged cylinders, a pair of rectilinear pistons in said cylinders, vsaid pistons being made as a unitary structure with a connecting web eccentrically positioned relative to the axis of the pistons, and a drive for said pistons comprising an eccentri'cally mounted rolling crank presented between the parallel inner ends of the pistons transversely of the axis thereof and opposite the said connecting web, said cylinders being made as separate units with a separate crank case connecting the same end to end, one of said pistons having a larger diameter than the other with the said cylinders made correspondingly, the smaller one of said pistons com prising a solid structure and the larger one having a hollow with an axial annular solid block-like structure within its hollow, the diameter of said block-like structure being equal to that of the diameter of the smaller solid piston and arranged co-axially thereof.

DEXTER C. BAKER. 

